Adding CLI for the migration tool

kubernetes/corefile-tool/.gitignore

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+Corefile
+corefile-tool
+*.yaml

kubernetes/corefile-tool/README.md

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+## Corefile-tool
+
+Corefile-tool is a simple command line tool which helps you to evaluate and migrate your CoreDNS Corefile Configuration.
+It is based on the [CoreDNS migration tool library](https://github.com/coredns/deployment/tree/master/kubernetes/migration).
+
+## Usage
+
+Use the following syntax to run the `corefile-tool` command:
+
+`corefile-tool [command] [flags]`
+
+where `command`, `flags` are:
+
+- `command`: The operation you want to perform. 
+- `flags`  : Specifies flags required to carry out the operations.
+
+
+### Operations
+
+The following operations are supported:
+- `default`: Default returns true if the Corefile is the default for a that version of Kubernetes. 
+If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.
+
+- `deprecated`    : Deprecated returns a list of deprecated plugins or directives present in the Corefile.
+- `migrate`       : Migrate your CoreDNS corefile.
+- `removed`       : Removed returns a list of removed plugins or directives present in the Corefile.
+- `unsupported`   : Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).
+- `validversions` : Shows valid versions of CoreDNS.
+
+
+### Examples
+
+The following examples will help you understand the basic usage of the migration tool.
+
+```bash
+# See if the Corefile is the default in CoreDNS v1.4.0. 
+corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile
+```
+
+```bash
+# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
+
+# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
+corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false
+```
+

kubernetes/corefile-tool/cmd/default.go

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+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewDefaultCmd represents the default command
+func NewDefaultCmd() *cobra.Command {
+	defaultCmd := &cobra.Command{
+		Use:   "default",
+		Short: "default returns true if the Corefile is the default for a that version of Kubernetes. If the Kubernetes version is omitted, returns true if the Corefile is the default for any version.",
+		Example: `# See if the Corefile is the default in CoreDNS v1.4.0. 
+corefile-tool default --k8sversion 1.4.0 --corefile /path/to/Corefile`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			k8sversion, _ := cmd.Flags().GetString("k8sversion")
+			corefile, _ := cmd.Flags().GetString("corefile")
+
+			isDefault, err := defaultCorefileFromPath(k8sversion, corefile)
+			if err != nil {
+				return fmt.Errorf("error while checking if the Corefile is the default: %v \n", err)
+			}
+			fmt.Println(isDefault)
+
+			return nil
+		},
+	}
+	defaultCmd.Flags().String("k8sversion", "", "The Kuberenetes version for which you are checking the default.")
+	defaultCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	defaultCmd.MarkFlagRequired("corefile")
+
+	return defaultCmd
+}
+
+// defaultCorefileFromPath takes the path where the Corefile is located and checks
+// if the Corefile is the default for that version of Kubernetes.
+func defaultCorefileFromPath(k8sVersion, corefilePath string) (bool, error) {
+	fileBytes, err := getCorefileFromPath(corefilePath)
+	if err != nil {
+		return false, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Default(k8sVersion, corefileStr), nil
+}

kubernetes/corefile-tool/cmd/deprecated.go

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+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewDeprecatedCmd represents the deprecated command
+func NewDeprecatedCmd() *cobra.Command {
+	deprecatedCmd := &cobra.Command{
+		Use:   "deprecated",
+		Short: "Deprecated returns a list of deprecated plugins or directives present in the Corefile.",
+		Example: `# See deprecated plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool deprecated --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			deprecated, err := deprecatedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, dep := range deprecated {
+				fmt.Println(dep.ToString())
+			}
+			return nil
+		},
+	}
+	deprecatedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	deprecatedCmd.MarkFlagRequired("from")
+	deprecatedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	deprecatedCmd.MarkFlagRequired("to")
+	deprecatedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	deprecatedCmd.MarkFlagRequired("corefile")
+
+	return deprecatedCmd
+}
+
+// deprecatedCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
+// present in the Corefile.
+func deprecatedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	fileBytes, err := getCorefileFromPath(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Deprecated(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}

kubernetes/corefile-tool/cmd/migrate.go

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+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewMigrateCmd represents the migrate command
+func NewMigrateCmd() *cobra.Command {
+	var migrateCmd = &cobra.Command{
+		Use:   "migrate",
+		Short: "Migrate your CoreDNS corefile",
+		Example: `# Migrate CoreDNS from v1.4.0 to v1.5.0 and handle deprecations . 
+corefile-tool migrate --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile  --deprecations true
+
+# Migrate CoreDNS from v1.2.2 to v1.3.1 and do not handle deprecations .
+corefile-tool migrate --from 1.2.2 --to 1.3.1 --corefile /path/to/Corefile  --deprecations false`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			deprecations, _ := cmd.Flags().GetBool("deprecations")
+
+			migrated, err := migrateCorefileFromPath(from, to, corefile, deprecations)
+			if err != nil {
+				return fmt.Errorf("error while migration: %v \n", err)
+			}
+			fmt.Println(migrated)
+			return nil
+		},
+	}
+	migrateCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	migrateCmd.MarkFlagRequired("from")
+	migrateCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	migrateCmd.MarkFlagRequired("to")
+	migrateCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	migrateCmd.MarkFlagRequired("corefile")
+	migrateCmd.Flags().Bool("deprecations", false, "Required: Specify whether you want to handle plugin deprecations. [True | False] ")
+	migrateCmd.MarkFlagRequired("deprecations")
+
+	return migrateCmd
+}
+
+// migrateCorefileFromPath takes the path where the Corefile is located and returns the deprecated plugins or directives
+// present in the Corefile.
+func migrateCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string, deprecations bool) (string, error) {
+	fileBytes, err := getCorefileFromPath(corefilePath)
+	if err != nil {
+		return "", err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Migrate(fromCoreDNSVersion, toCoreDNSVersion, corefileStr, deprecations)
+}

kubernetes/corefile-tool/cmd/removed.go

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+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewRemovedCmd represents the removed command
+func NewRemovedCmd() *cobra.Command {
+	removedCmd := &cobra.Command{
+		Use:   "removed",
+		Short: "Removed returns a list of removed plugins or directives present in the Corefile.",
+		Example: `# See removed plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool removed --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			removed, err := removedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, rem := range removed {
+				fmt.Println(rem.ToString())
+			}
+			return nil
+		},
+
+	}
+	removedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	removedCmd.MarkFlagRequired("from")
+	removedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	removedCmd.MarkFlagRequired("to")
+	removedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	removedCmd.MarkFlagRequired("corefile")
+
+	return removedCmd
+}
+
+// removedCorefileFromPath takes the path where the Corefile is located and returns the plugins or directives
+// that have been removed.
+func removedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	fileBytes, err := getCorefileFromPath(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Removed(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}

kubernetes/corefile-tool/cmd/root.go

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+package cmd
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/lithammer/dedent"
+	"github.com/spf13/cobra"
+)
+
+// CorefileTool represents the base command for the corefile-tool.
+func CorefileTool() *cobra.Command {
+	rootCmd := &cobra.Command{
+		Use:   "corefile-tool",
+		Short: "A brief description of your application",
+		Long: dedent.Dedent(`
+
+			    ┌──────────────────────────────────────────────────────────┐
+			    │ CoreDNS Migration Tool                                   │
+			    │ Easily Migrate your Corefile                             │
+			    │                                                          │
+			    │ Please give us feedback at:                              │
+			    │ https://github.com/coredns/deployment/issues             │
+			    └──────────────────────────────────────────────────────────┘
+
+		`),
+	}
+	rootCmd.AddCommand(NewRemovedCmd())
+	rootCmd.AddCommand(NewMigrateCmd())
+	rootCmd.AddCommand(NewDefaultCmd())
+	rootCmd.AddCommand(NewDeprecatedCmd())
+	rootCmd.AddCommand(NewUnsupportedCmd())
+	rootCmd.AddCommand(NewValidVersionsCmd())
+
+	return rootCmd
+}
+
+// Execute adds all child commands to the root command and sets flags appropriately.
+func Execute() {
+	if err := CorefileTool().Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+
+func getCorefileFromPath(corefilePath string) ([]byte, error) {
+	if _, err := os.Stat(corefilePath); os.IsNotExist(err) {
+		return nil, err
+	}
+
+	fileBytes, err := ioutil.ReadFile(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+
+	return fileBytes, nil
+}

kubernetes/corefile-tool/cmd/unsupported.go

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+package cmd
+
+import (
+	"fmt"
+
+	"github.com/coredns/deployment/kubernetes/migration"
+
+	"github.com/spf13/cobra"
+)
+
+// NewUnsupportedCmd represents the unsupported command
+func NewUnsupportedCmd() *cobra.Command {
+	unsupportedCmd := &cobra.Command{
+		Use:   "unsupported",
+		Short: "Unsupported returns a list of plugins that are not recognized/supported by the migration tool (but may still be valid in CoreDNS).",
+		Example: `# See unsupported plugins CoreDNS from v1.4.0 to v1.5.0. 
+corefile-tool unsupported --from 1.4.0 --to 1.5.0 --corefile /path/to/Corefile`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			from, _ := cmd.Flags().GetString("from")
+			to, _ := cmd.Flags().GetString("to")
+			corefile, _ := cmd.Flags().GetString("corefile")
+			unsupported, err := unsupportedCorefileFromPath(from, to, corefile)
+			if err != nil {
+				return fmt.Errorf("error while listing deprecated plugins: %v \n", err)
+			}
+			for _, unsup := range unsupported {
+				fmt.Println(unsup.ToString())
+			}
+			return nil
+		},
+	}
+
+	unsupportedCmd.Flags().String("from", "", "Required: The version you are migrating from. ")
+	unsupportedCmd.MarkFlagRequired("from")
+	unsupportedCmd.Flags().String("to", "", "Required: The version you are migrating to.")
+	unsupportedCmd.MarkFlagRequired("to")
+	unsupportedCmd.Flags().String("corefile", "", "Required: The path where your Corefile is located.")
+	unsupportedCmd.MarkFlagRequired("corefile")
+
+	return unsupportedCmd
+}
+
+// unsupportedCorefileFromPath takes the path where the Corefile is located and returns a list of  plugins
+// that have been removed.
+func unsupportedCorefileFromPath(fromCoreDNSVersion, toCoreDNSVersion, corefilePath string) ([]migration.Notice, error) {
+	fileBytes, err := getCorefileFromPath(corefilePath)
+	if err != nil {
+		return nil, err
+	}
+	corefileStr := string(fileBytes)
+	return migration.Unsupported(fromCoreDNSVersion, toCoreDNSVersion, corefileStr)
+}